Acetyl-L-Carnitine

ALCAR · Acetylcarnitine · Levacecarnine

Snapshot

Indications	Contraindications
Depressive symptoms¹ Diabetic peripheral neuropathy² Fibromyalgia pain^{3, 4} Sperm motility in male infertility⁵ Blood ammonia in cirrhosis⁶ Vascular cognitive impairment⁷ Erectile dysfunction with sildenafil⁸	Taxane chemotherapy^{9, 10} Pregnancy or lactation¹¹

Acetyl-L-carnitine is the acetyl ester of L-carnitine, which carries fatty acids into mitochondria and donates acetyl groups, with effects on neurons as well as muscle¹². That mitochondrial and neuronal support drives its use for depressive symptoms, particularly in older adults, and for painful peripheral neuropathy in diabetes. It is also taken for idiopathic male infertility, fibromyalgia, cognitive decline, and hepatic encephalopathy.

For diabetic neuropathy pain a Cochrane review found very low-certainty evidence, and in dementia another found no benefit on objective measures. In mice exposed to prenatal trauma, a 2021 study found early supplementation protected against depressive-like behavior; it was not a human trial¹³. Products are mainly capsules, among more than 4,000 products listing acetyl-L-carnitine; see Form comparison.

The most consequential caution is chemotherapy-induced neuropathy: in women receiving taxane chemotherapy, supplementation worsened neuropathy by 24 weeks in a randomized trial, and the authors advised against supplements without proven efficacy⁹. One US product label warns of interaction with anticoagulant medications¹¹.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

87 sources, 73 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources